1. Field of the Invention
This invention relates to conductive interconnect structures for use in integrated circuits and in particular to a binary conductive material comprising a germanium-silicon binary alloy suitable for use both as a conductive interconnect and as a conductive gate.
2. Description of the Prior Art
Integrated circuits comprise a plurality of selectively doped regions formed in semiconductor material interconnected by conductive leads formed on and adherent to insulation overlying the semiconductor material. A typical conductive interconnect structure is disclosed in U.S. Pat. No. 2,981,877 entitled "Semiconductor Device-and-Lead Structure" issued Apr. 25, 1961 on an invention of Noyce. Typically the interconnect leads adhering to the surface of the semiconductor device are formed of a conductive material such as aluminum or doped polycrystalline silicon. One problem with aluminum is that it melts at approximately 650.degree. C. thereby making unfeasible high temperature processing of the integrated circuit following the deposition of aluminum. While doped polycrystalline silicon has a much higher melting temperature and thus avoids this problem, the resistivity of even doped polycrystalline silicon is sufficiently higher than that of metal to significantly reduce the speed of operation of an integrated circuit. Accordingly, it would be advantageous to find a material which is appropriate for use as conductive interconnects and contact regions on integrated circuits and which possesses a lower resistivity than polycrystalline silicon and which is capable of sustaining higher temperatures than aluminum.